Reported by HTamura in the DukeDollars newsgroup

the JVMDI interface allows you to set a breakpoint on any bytecode and
doesn't seem to report an error setting bci
to 0,1,7 is ok
2 you get null pointer
and 3,4,6,7,9 a core dump

when code is
Method void main(java.lang.String[])
   0 iconst_2
   1 istore_1
   2 getstatic #9 <Field java.io.PrintStream out>
   5 ldc #1 <String "Hello">
   7 invokevirtual #10 <Method void println(java.lang.String)>
  10 return

Test.java
public class Test
{
    static {
        System.loadLibrary("Test");
        startDebugger();
    }

    static native void startDebugger();

    public static void main(String args[]) {
        int i=2;
        System.out.println("Hello");
    }
}

Test.c
#include <jni.h>
#include <jvmdi.h>
#include <stdio.h>
#include "Test.h"
void Hook(JNIEnv *env, JVMDI_Event *event)
{
    printf("Hook is called.\n");
    if ( event->kind == JVMDI_EVENT_BREAKPOINT ) {
        printf("BP hit\n");
    } else {
        printf("Other event occurrred.\n");
    }
    return;
}

JNIEXPORT void JNICALL Java_Test_startDebugger(JNIEnv *env, jclass cls)
{
    jvmdiError err;
    jmethodID mid;
    int bci = 3; /* variable */

    mid = (*env)->GetStaticMethodID(env, cls, "main", "([Ljava/lang/String;)V");
    if ( mid == 0 ) return;
    printf("Now I'll set BP.\n");
    err = JVMDI_SetBreakpoint(env, cls, mid, bci);
        printf("err=",err);
    if ( err != JVMDI_ERROR_NONE ) {
        printf("Error\n");
        return;
    }
    printf("Done.\n");
  printf("Now I'll set hook.\n");
    err = JVMDI_SetEventHook(env, Hook);
    if ( err != JVMDI_ERROR_NONE ) {
        printf("Error\n");
        return;
    }
    printf("Done.\n");
}